How Does One “get A Lawyer”?

Apologies if this has been asked here before, didn’t find what I was looking for from a quick search. Asking from the U.S.

I don’t plan on needing this advice anytime soon! But I am curious specifically in this context: if you are in police custody and want a lawyer, how does someone go about establishing a relationship with someone other than a public defender?

In TV/movies you see people say “I want to talk to my lawyer” and they end up with a seasoned professional next to them at the table hours later…I understand this is obviously a dramatization, but in the real world is the expectation that it’s part of adult life to have an attorney in the same way that you have a doctor and a dentist? I’m in my late 20s and definitely missed that if that’s the case.

I’ve gotten interested lately in legal things and in particular some of the details about how talking directly to the police in any legal situation other than a traffic stop is a truly terrible idea. It’s gotten me thinking: “if I was ever arrested and had to ask for an attorney…what comes next?”

To be totally clear, I’m not asking how I should go about searching for attorneys in my area from my couch right now, but whether a) that is a relationship that is a smart thing to establish proactively for anyone, and b) how people are expected to get a good lawyer if they are in custody and don’t have one already.

Edit: thanks all for the quick answers!